The episode, written by co-executive producer Robert Hull and directed by Rob Bailey, was first broadcast on June 5, 2017.
Gordon and Bullock take Cobblepot to a factory where Nygma holds Tetch with a bomb connected to him in order to kill him if the deal goes awry.
Seeing they cannot escape in time, Gordon cuts Tetch's throat to retrieve his blood for the antidote, and he and Bullock return to the GCPD to develop the cure.
They argue and then begin fighting, culminating in Tabitha using her whip to knock down a construction light that electrocutes and kills Barbara.
Wanting to find security and influence, Selina goes to The Sirens Club and joins Tabitha, even testing her whip.
In March 2017, Drew Powell announced that the twenty-second and final episode of the season would be titled "Heavydirtysoul" and was to be written by Robert Hull and directed by Rob Bailey.
[3] In August 2016, the producers talked about introducing Harley Quinn into the series despite the character's success in the film Suicide Squad.
[9] While Quinn did not physically appear during the show's run, she was briefly referenced in the series finale by Jeremiah Valeska.
In May 2017, it was announced that the guest cast for the episode would include Jada Pinkett Smith as Fish Mooney, Alexander Siddig as Ra's al Ghul, Camila Perez as Bridgit Pike/Firefly, Nathan Darrow as Victor Fries/Mr.
"[3] Nick Hogan of TV Overmind gave the episode a 4.5 star rating out of 5, writing "With exception to my one little quibble, the finale of Gotham proved to be a launching point toward the Batman story.
"[21] Amanda Bell of EW gave the episode a "B" and wrote, "This half of Gotham's third season has been filled with so many moving parts that, at times, it's been a bit dizzying to keep track of who wants to kill whom and why.
But tonight's two-part finale sews up those dangling threads rather seamlessly and presents a new and, dare I say, optimistic vision for the future of this city.
"[22] Vinnie Mancuso of Collider wrote, "Gotham's two-part Season 3 finale took the series' most significant step forward, even offering up a proto-Dark Knight, in an effort to merge who these characters are with the figures they become.
Like all great Batman stories, it did so by circling back to my original question, and attempting to show the true face of Gotham City itself.
"[23] Lisa Babick of TV Fanatic gave the series a perfect 5 star rating out of 5, writing "Gotham finished off its third season with a two-hour finale that was mind-blowing in every way possible.
"[24] Kayti Burt of Den of Geek wrote, "It feels like a new chapter in this show is starting -- one that may finally see Gotham's heroes given the same narrative chances as its villains.
"[25] Megan Vick of TV Guide wrote, "For an ending, it's a promising beginning to the show's upcoming fourth season.